[Lexical tone perception in sensorineural hearing-impaired and auditory neuropathy spectrum disorder]

This study was aimed at investigating the ability of lexical tone perception in listeners with sensorineural hearing impairment and auditory. neuropathy spectrum disorder.

Three groups of subjects were recruited in this study, including 11 subjects with normal hearing, 14 subjects with sensorineural hearing impairment, and 25 subjects with auditory neuropathy spectrum disorder. Ten monosyllabic syllables were selected, and combined with four lexical tones which were made up of 40 tone tokens as the original test materials. Then, these original words were recorded using one adult male and one adult female native Beijing Mandarin speaker. The speakers were asked to record these 40 monosyllabic words multiple times, and the 80 tokens in which the durations of four tones in each monosyllabic word were within 5ms precision were chosen as the test tone tokens. The subjects were asked to perform a four-alternative forced-choice study and select which tone they had heard.

The mean and standard deviation of the tone perception correct scores for normal-hearing subjects, subjects with sensorineural hearing impairment, and subjects with auditory neuropathy spectrum disorder were (97.3 ± 2.8)%, (88.0 ± 9.9)%, and (65.7 ± 17.1)%, respectively. Significant differences in tone perception scores were found to be between subjects with normal hearing and subjects with sensorineural hearing impairment (P < 0.01) and between subjects with auditory neuropathy spectrum disorder (P < 0.01). In addition, a significant difference was found to be between subjects with sensorineural hearing impairment and auditory neuropathy spectrum disorder (P < 0.05). A significantly negative correlation was observed between tone perception score and pure tone hearing thresholds for both subjects with sensorineural hearing loss (r = -0.756, P < 0.01) and subjects with auditory neuropathy spectrum disorder (r = -0.546, P < 0.01).

As the hearing loss became more severe, the ability to perceive lexical tone for both subjects with sensorineural hearing loss and auditory neuropathy spectrum disorder reduced. Subjects with auditory neuropathy spectrum disorder had more degraded ability to perceive lexical tone and a larger individual difference, in comparison with subjects with sensorineural hearing loss.